title: Ethnicity-specific birthweight distributions improve identification of term newborns at risk for short-term morbidity.
abstract: OBJECTIVE
  We aimed to determine whether ethnicity-specific birthweight distributions more accurately identify newborns at risk for short-term neonatal morbidity associated with small for gestational age (SGA) birth than population-based distributions not stratified on ethnicity.
  
  
  METHODS
  We examined 100,463 singleton term infants born to parents in Washington State between Jan. 1, 2006, and Dec. 31, 2008. Using multivariable logistic regression models, we compared the ability of an ethnicity-specific growth distribution and a population-based growth distribution to predict which infants were at increased risk for Apgar score <7 at 5 minutes, admission to the neonatal intensive care unit, ventilation, extended length of stay in hospital, hypothermia, hypoglycemia, and infection.
  
  
  RESULTS
  Newborns considered SGA by ethnicity-specific weight distributions had the highest rates of each of the adverse outcomes assessed-more than double those of infants only considered SGA by the population-based standards. When controlling for mother's age, parity, body mass index, education, gestational age, mode of delivery, and marital status, newborns considered SGA by ethnicity-specific birthweight distributions were between 2 and 7 times more likely to suffer from the adverse outcomes listed above than infants who were not SGA. In contrast, newborns considered SGA by population-based birthweight distributions alone were at no higher risk of any adverse outcome except hypothermia (adjusted odds ratio, 2.76; 95% confidence interval, 1.68-4.55) and neonatal intensive care unit admission (adjusted odds ratio, 1.40; 95% confidence interval, 1.18-1.67).
  
  
  CONCLUSIONS
  Ethnicity-specific birthweight distributions were significantly better at identifying the infants at higher risk of short-term neonatal morbidity, suggesting that their use could save resources and unnecessary parental anxiety.
authors.affiliation: School of Population and Public Health and the Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Gillian E
authors.initials: GE
authors.lastname: Hanley
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Janssen
mesh_terms: D000328:Adult; D001211:Asia, Western / Q000208:ethnology; D001213:Asian / Q000706:statistics & numerical data*; D001724:Birth Weight; D002681:China / Q000208:ethnology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008297:Male; D011247:Pregnancy; D018570:Risk Assessment; D016008:Statistical Distributions; D014861:Washington; D044465:White People / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: ethnicity; fetal growth; small for gestational age